function externallinks() {

if (!document.getElementsByTagName) return;

	var anchors = document.getElementsByTagName("a");

	for (var i=0; i<anchors.length; i++) {

	var anchor = anchors[i];

	if (anchor.getAttribute("href") &&

		anchor.getAttribute("rel") == "external")

		anchor.target = "_blank";

	}

}

window.onload = externallinks;